(19)
(11) EP 0 339 855 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.03.1992 Bulletin 1992/11

(43) Date of publication A2:
02.11.1989 Bulletin 1989/44

(21) Application number: 89303854.7

(22) Date of filing: 19.04.1989
(51) International Patent Classification (IPC)4: H04R 9/04, H04R 9/02
(84) Designated Contracting States:
AT DE FR GB IT NL

(30) Priority: 27.04.1988 JP 104596/88
17.05.1988 JP 120233/88
23.05.1988 JP 125387/88

(60) Divisional application:
94103841.6 / 0605400

(71) Applicant: SONY CORPORATION
Tokyo 141 (JP)

(72) Inventors:
  • Inanaga, Kiyofumi c/o Patents Division
    Shinagawa-ku Tokyo 141 (JP)
  • Sogawa, Hiroyuki c/o Patents Division
    Shinagawa-ku Tokyo 141 (JP)
  • Tsukamoto, Shiro c/o Patents Division
    Shinagawa-ku Tokyo 141 (JP)

(74) Representative: Cotter, Ivan John et al
D. YOUNG & CO. 21 New Fetter Lane
London EC4A 1DA
London EC4A 1DA (GB)


(56) References cited: : 
   
       


    (54) Electrodynamic loudspeaker


    (57) A loudspeaker (21) comprises a diaphragm (22) having a vibrating portion (215) and an annular conductive portion (28), a current feeding coil (23) facing the conductive portion (28) with a predetermined magnetic gap, and a magnetic circuit (24, 25, 26, 211) comprising a top plate (24), a magnet (25) and a yoke plate (26) to which the current feeding coil (23) is attached, the diaphragm (22) being formed so that the electric resistance of the conductive portion (28) is lower than the electric resistance of the vibrating portion (215).







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